A conventional laser machining apparatus is configured to machine a workpiece by irradiating a laser beam thereon. The irradiated laser beam is progressively scanned to irradiate desired positions on the workpiece in order to machine patterns depicting characters, symbols, and the like.
One such laser machining apparatus known in the art is provided with a laser beam emitting device and a pump light emitting device. In this laser machining apparatus, the pump light emitting device is configured to emit pump light corresponding to a magnitude of a drive current when the drive current is supplied to the pump light emitting device. The laser beam emitting device is configured to transit from a ground state to a pumped state to emit a laser beam for machining the workpiece when the pump light is incident upon the laser beam emitting device.
Since this transition from the ground state to the pumped state and other processes require some time, this type of a laser machining apparatus may experience a time lapse after the drive current is first supplied and before a laser beam having desired output intensity is emitted and, hence, the output intensity of the laser beam may not be sufficiently strong at the start of the machining process. Such insufficient laser output intensity at the start of the machining process may lead to a decline in machining quality. For example, the laser beam may be unable to machine the laser irradiation start portion or may produce an insufficient depth of cut at the start of the machining process.
In order to address these shortcomings, a laser machining apparatus disclosed in Japanese Patent Application Publication No. 2004-337970 first supplies an initial drive current corresponding to laser output intensity higher than a prescribed laser output intensity to exciting means (an example of the pump light emitting device), and subsequently supplies a drive current corresponding to the prescribed laser output intensity to the exciting means. The laser machining apparatus disclosed in the above-stated literature reduces the time period required for the laser beam emitting device to transit to the pumped state and to output a laser beam having the desired output intensity by first supplying the initial drive current. Further, since the rising time of the laser output intensity is improved, the laser machining apparatus can suppress a decline in machining quality caused by the insufficient laser output intensity at the start of the machining process.